As the wireless communications industry blooms, the fast development of wireless transmissions brings in various products and technologies that are used in multiple-frequency transmissions. Thus, many products are equipped with the wireless transmission capability to meet consumer requirements. In addition, it is very important for a wireless transmission product to have a good antenna.
In general, conventional antennas for wireless transmission products are divided into two types: Planar Inverted F Antenna (PIFA) and dual-frequency dipole antenna, and both types have an operating mode that resonates at ¼ wavelength. Further, these conventional antennas can only provide a single frequency band for its operation. As the market grows and the technology advances, a single frequency band no longer can meet the market requirement. Therefore, the present invention provides an antenna that can be operated in a dual-frequency mode.